diff --git a/_doc/sphinxdoc/source/blog/2015/2015-12-12_sphinx_extensions.rst b/_doc/sphinxdoc/source/blog/2015/2015-12-12_sphinx_extensions.rst
index d1e1db08..10c5b5dc 100644
--- a/_doc/sphinxdoc/source/blog/2015/2015-12-12_sphinx_extensions.rst
+++ b/_doc/sphinxdoc/source/blog/2015/2015-12-12_sphinx_extensions.rst
@@ -12,7 +12,6 @@
     `Sphinx <http://sphinx-doc.org/>`_ documentation:
 
     * `imagesvg <https://pypi.python.org/pypi/sphinxcontrib-imagesvg/>`_: to include svg figures
-    * `jsdemo <https://pypi.python.org/pypi/sphinxcontrib-imagesvg/>`_: to demo javascript and HTML
 
     .. demo::
 
diff --git a/_unittests/ut_sphinxext/test_style_doc.py b/_unittests/ut_sphinxext/test_style_doc.py
index 1af14be2..57322e92 100644
--- a/_unittests/ut_sphinxext/test_style_doc.py
+++ b/_unittests/ut_sphinxext/test_style_doc.py
@@ -26,7 +26,6 @@ def test_docstyle(self):
         extensions = [_ for _ in extensions if "matplotlib" not in _ and
                       "images" not in _ and "IPython" not in _ and
                       "nbsphinx" not in _ and "jupyter" not in _ and
-                      "jsdemo" not in _ and
                       "inheritance_diagram" not in _]
         external_docnames = [
             "_modules/src/pyquickhelper/helpgen/_fake_function_to_documentation"]
diff --git a/requirements.txt b/requirements.txt
index 6377dbc5..3c64a2c3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -46,10 +46,9 @@ PyYAML
 scipy
 semantic_version
 setuptools
-Sphinx>=3.0,<4.0
+Sphinx>=3.0
 sphinx-gallery
 sphinxcontrib-imagesvg
-sphinxcontrib-jsdemo
 sphinx_rtd_theme
 tabulate
 tqdm
diff --git a/setup.py b/setup.py
index e090ac05..4261c9d1 100644
--- a/setup.py
+++ b/setup.py
@@ -136,7 +136,7 @@
             'pysftp',
             "requests",
             "semantic_version",
-            "sphinx>=3.0,<4.0",
+            "sphinx>=3.0",
             "sphinx-gallery",
             "sphinxcontrib-imagesvg",
             "traitlets>=5.0",
diff --git a/src/pyquickhelper/helpgen/default_conf.py b/src/pyquickhelper/helpgen/default_conf.py
index 49c0041d..9c03e511 100644
--- a/src/pyquickhelper/helpgen/default_conf.py
+++ b/src/pyquickhelper/helpgen/default_conf.py
@@ -569,14 +569,6 @@ def set_sphinx_variables(fileconf, module_name, author, year, theme, theme_path,
         # matplotlib is not installed.
         pass
 
-    try:
-        import sphinxcontrib.jsdemo
-        assert sphinxcontrib.jsdemo is not None
-        extensions.append('sphinxcontrib.jsdemo')
-    except ImportError:  # pragma: no cover
-        # No module sphinxcontrib.jsdemo.
-        pass
-
     if use_lunrsearch:  # pragma: no cover
         extensions.append('sphinxcontrib.lunrsearch')
 
diff --git a/src/pyquickhelper/helpgen/sphinxm_convert_doc_sphinx_helper.py b/src/pyquickhelper/helpgen/sphinxm_convert_doc_sphinx_helper.py
index 45c62ef9..9594693b 100644
--- a/src/pyquickhelper/helpgen/sphinxm_convert_doc_sphinx_helper.py
+++ b/src/pyquickhelper/helpgen/sphinxm_convert_doc_sphinx_helper.py
@@ -26,9 +26,11 @@
 from sphinx.project import Project
 from sphinx.errors import ApplicationError
 from sphinx.util.logging import getLogger
-from ..sphinxext.sphinx_doctree_builder import DocTreeBuilder, DocTreeWriter, DocTreeTranslator
+from ..sphinxext.sphinx_doctree_builder import (
+    DocTreeBuilder, DocTreeWriter, DocTreeTranslator)
 from ..sphinxext.sphinx_md_builder import MdBuilder, MdWriter, MdTranslator
-from ..sphinxext.sphinx_latex_builder import EnhancedLaTeXBuilder, EnhancedLaTeXWriter, EnhancedLaTeXTranslator
+from ..sphinxext.sphinx_latex_builder import (
+    EnhancedLaTeXBuilder, EnhancedLaTeXWriter, EnhancedLaTeXTranslator)
 from ..sphinxext.sphinx_rst_builder import RstBuilder, RstWriter, RstTranslator
 from ._single_file_html_builder import CustomSingleFileHTMLBuilder
 
@@ -171,8 +173,8 @@ class HTMLTranslatorWithCustomDirectives(_AdditionalVisitDepart, HTMLTranslator)
     See @see cl HTMLWriterWithCustomDirectives.
     """
 
-    def __init__(self, builder, *args, **kwds):
-        HTMLTranslator.__init__(self, builder, *args, **kwds)
+    def __init__(self, document, builder, *args, **kwds):
+        HTMLTranslator.__init__(self, document, builder, *args, **kwds)
         _AdditionalVisitDepart.__init__(self, 'html')
         nodes_list = getattr(builder, '_function_node', None)
         if nodes_list is not None:
@@ -201,11 +203,11 @@ class RSTTranslatorWithCustomDirectives(_AdditionalVisitDepart, RstTranslator):
     See @see cl HTMLWriterWithCustomDirectives.
     """
 
-    def __init__(self, builder, *args, **kwds):
+    def __init__(self, document, builder, *args, **kwds):
         """
         constructor
         """
-        RstTranslator.__init__(self, builder, *args, **kwds)
+        RstTranslator.__init__(self, document, builder, *args, **kwds)
         _AdditionalVisitDepart.__init__(self, 'rst')
         for name, f1, f2 in builder._function_node:
             setattr(self.__class__, "visit_" + name, f1)
@@ -218,11 +220,11 @@ class MDTranslatorWithCustomDirectives(_AdditionalVisitDepart, MdTranslator):
     See @see cl HTMLWriterWithCustomDirectives.
     """
 
-    def __init__(self, builder, *args, **kwds):
+    def __init__(self, document, builder, *args, **kwds):
         """
         constructor
         """
-        MdTranslator.__init__(self, builder, *args, **kwds)
+        MdTranslator.__init__(self, document, builder, *args, **kwds)
         _AdditionalVisitDepart.__init__(self, 'md')
         for name, f1, f2 in builder._function_node:
             setattr(self.__class__, "visit_" + name, f1)
@@ -235,11 +237,11 @@ class DocTreeTranslatorWithCustomDirectives(DocTreeTranslator):
     See @see cl HTMLWriterWithCustomDirectives.
     """
 
-    def __init__(self, builder, *args, **kwds):
+    def __init__(self, document, builder, *args, **kwds):
         """
         constructor
         """
-        DocTreeTranslator.__init__(self, builder, *args, **kwds)
+        DocTreeTranslator.__init__(self, document, builder, *args, **kwds)
         self.base_class = DocTreeTranslator
 
 
@@ -248,7 +250,7 @@ class LatexTranslatorWithCustomDirectives(_AdditionalVisitDepart, EnhancedLaTeXT
     See @see cl LatexWriterWithCustomDirectives.
     """
 
-    def __init__(self, builder, document, *args, **kwds):
+    def __init__(self, document, builder, *args, **kwds):
         """
         constructor
         """
@@ -258,7 +260,7 @@ def __init__(self, builder, document, *args, **kwds):
             raise TypeError(  # pragma: no cover
                 "Builder has no config: {} - {}".format(type(builder), type(document)))
         EnhancedLaTeXTranslator.__init__(
-            self, builder, document, *args, **kwds)
+            self, document, builder, *args, **kwds)
         _AdditionalVisitDepart.__init__(self, 'md')
         for name, f1, f2 in builder._function_node:
             setattr(self.__class__, "visit_" + name, f1)
@@ -319,9 +321,6 @@ def write(self, document, destination):
 
         Normally not overridden or extended in subclasses.
         """
-        # trans = self.builder.create_translator(self.builder, document)
-        # if not isinstance(trans, HTMLTranslatorWithCustomDirectives):
-        #     raise TypeError("The translator is not of a known type but '{0}'".format(type(trans)))
         self.base_class.write(self, document, destination)
 
 
@@ -347,7 +346,7 @@ def __init__(self, builder=None, app=None):  # pylint: disable=W0231
 
     def translate(self):
         self.visitor = visitor = self.translator_class(
-            self.builder, self.document)
+            self.document, self.builder)
         self.document.walkabout(visitor)
         self.output = visitor.astext()
         for attr in ('head_prefix', 'stylesheet', 'head', 'body_prefix',
@@ -374,7 +373,7 @@ def __init__(self, builder=None, app=None):  # pylint: disable=W0231
             self, RstWriter, RSTTranslatorWithCustomDirectives, app)
 
     def translate(self):
-        visitor = self.translator_class(self.builder, self.document)
+        visitor = self.translator_class(self.document, self.builder)
         self.document.walkabout(visitor)
         self.output = visitor.body
 
@@ -394,7 +393,7 @@ def __init__(self, builder=None, app=None):  # pylint: disable=W0231
             self, MdWriter, MDTranslatorWithCustomDirectives, app)
 
     def translate(self):
-        visitor = self.translator_class(self.builder, self.document)
+        visitor = self.translator_class(self.document, self.builder)
         self.document.walkabout(visitor)
         self.output = visitor.body
 
@@ -414,7 +413,7 @@ def __init__(self, builder=None, app=None):  # pylint: disable=W0231
             self, DocTreeWriter, DocTreeTranslatorWithCustomDirectives, app)
 
     def translate(self):
-        visitor = self.translator_class(self.builder, self.document)
+        visitor = self.translator_class(self.document, self.builder)
         self.document.walkabout(visitor)
         self.output = visitor.body
 
@@ -441,10 +440,10 @@ def translate(self):
             raise TypeError(  # pragma: no cover
                 "Builder has no config: {}".format(type(self.builder)))
         # The instruction
-        # visitor = self.builder.create_translator(self.builder, self.document)
+        # visitor = self.builder.create_translator(self.document, self.builder)
         # automatically adds methods visit_ and depart_ for translator
         # based on the list of registered extensions. Might be worth using it.
-        visitor = self.translator_class(self.builder, self.document)
+        visitor = self.translator_class(self.document, self.builder)
         self.document.walkabout(visitor)
         self.output = visitor.body
 
@@ -1208,7 +1207,7 @@ def _citems():
 
         # create the project
         self.project = Project(self.srcdir, self.config.source_suffix)
-        # create the builder
+        # create the builder, initializes _MemoryBuilder
         self.builder = self.create_builder(buildername)
         # set up the build environment
         self._init_env(freshenv)
@@ -1221,9 +1220,17 @@ def _citems():
 
         # addition
         self._extended_init_()
+        
+        # verification
+        self._check_init_()
+    
+    def _check_init_(self):
+        pass
 
     def _init_env(self, freshenv):
-        if freshenv:
+        ENV_PICKLE_FILENAME = 'environment.pickle'
+        filename = os.path.join(self.doctreedir, ENV_PICKLE_FILENAME)
+        if freshenv or not os.path.exists(filename):
             self.env = _CustomBuildEnvironment(self)
             self.env.setup(self)
             if self.srcdir is not None and self.srcdir != "IMPOSSIBLE:TOFIND":
diff --git a/src/pyquickhelper/sphinxext/__init__.py b/src/pyquickhelper/sphinxext/__init__.py
index b914ddf5..83106205 100644
--- a/src/pyquickhelper/sphinxext/__init__.py
+++ b/src/pyquickhelper/sphinxext/__init__.py
@@ -158,12 +158,4 @@ def get_default_standard_extensions(use_mathjax=False):
         'matplotlib.sphinxext.plot_directive',
     ]
 
-    try:
-        import sphinxcontrib.jsdemo
-        assert sphinxcontrib.jsdemo is not None
-        extensions.append('sphinxcontrib.jsdemo')
-    except ImportError:  # pragma: no cover
-        # No module sphinxcontrib.jsdemo.
-        pass
-
     return extensions
diff --git a/src/pyquickhelper/sphinxext/sphinx_doctree_builder.py b/src/pyquickhelper/sphinxext/sphinx_doctree_builder.py
index 6387d7fa..f790c188 100644
--- a/src/pyquickhelper/sphinxext/sphinx_doctree_builder.py
+++ b/src/pyquickhelper/sphinxext/sphinx_doctree_builder.py
@@ -20,7 +20,7 @@ class DocTreeTranslator(nodes.NodeVisitor, CommonSphinxWriterHelpers):
     Defines a translator for doctree
     """
 
-    def __init__(self, builder, document):
+    def __init__(self, document, builder):
         if not hasattr(builder, 'config'):
             raise TypeError(  # pragma: no cover
                 "Unexpected type for builder {0}".format(type(builder)))
@@ -262,7 +262,7 @@ def __init__(self, builder):
         self.builder = builder
 
     def translate(self):
-        visitor = self.builder.create_translator(self.builder, self.document)
+        visitor = self.builder.create_translator(self.document, self.builder)
         self.document.walkabout(visitor)
         self.output = visitor.body
 
diff --git a/src/pyquickhelper/sphinxext/sphinx_latex_builder.py b/src/pyquickhelper/sphinxext/sphinx_latex_builder.py
index 4e243a65..dc5a1611 100644
--- a/src/pyquickhelper/sphinxext/sphinx_latex_builder.py
+++ b/src/pyquickhelper/sphinxext/sphinx_latex_builder.py
@@ -35,7 +35,7 @@ class EnhancedLaTeXTranslator(LaTeXTranslator):
     and modifies a few functions.
     """
 
-    def __init__(self, builder, document):
+    def __init__(self, document, builder):
         if not hasattr(builder, 'config'):
             raise TypeError(
                 "Unexpected type for builder {0}".format(type(builder)))
@@ -183,7 +183,7 @@ def __init__(self, builder):
         LaTeXWriter.__init__(self, builder)
 
     def translate(self):
-        visitor = self.builder.create_translator(self.builder, self.document)
+        visitor = self.builder.create_translator(self.document, self.builder)
         self.document.walkabout(visitor)
         self.output = visitor.astext()
 
@@ -259,8 +259,8 @@ def write(self, *ignored):
                 docname, toctree_only,
                 appendices=((docclass != 'howto') and self.config.latex_appendices or []))
             doctree['tocdepth'] = tocdepth
-            self.apply_transforms(doctree)
             self.post_process_images(doctree)
+            
             self.logger.info(__("writing... "), nonl=1)
             doctree.settings = docsettings
             doctree.settings.author = author
diff --git a/src/pyquickhelper/sphinxext/sphinx_md_builder.py b/src/pyquickhelper/sphinxext/sphinx_md_builder.py
index 094387c9..65afe269 100644
--- a/src/pyquickhelper/sphinxext/sphinx_md_builder.py
+++ b/src/pyquickhelper/sphinxext/sphinx_md_builder.py
@@ -54,7 +54,7 @@ class MdTranslator(TextTranslator, CommonSphinxWriterHelpers):
     Defines a :epkg:`MD` translator.
     """
 
-    def __init__(self, builder, document):
+    def __init__(self, document, builder):
         if not hasattr(builder, "config"):
             raise TypeError(  # pragma: no cover
                 "Builder has no config: {}".format(type(builder)))
@@ -1101,7 +1101,7 @@ def __init__(self, builder):
         self.builder = builder
 
     def translate(self):
-        visitor = self.builder.create_translator(self.builder, self.document)
+        visitor = self.builder.create_translator(self.document, self.builder)
         self.document.walkabout(visitor)
         self.output = visitor.body
 
diff --git a/src/pyquickhelper/sphinxext/sphinx_rst_builder.py b/src/pyquickhelper/sphinxext/sphinx_rst_builder.py
index aa4a85fd..e416b998 100644
--- a/src/pyquickhelper/sphinxext/sphinx_rst_builder.py
+++ b/src/pyquickhelper/sphinxext/sphinx_rst_builder.py
@@ -65,7 +65,7 @@ class RstTranslator(TextTranslator, CommonSphinxWriterHelpers):
     """
     sectionchars = '*=-~"+`'
 
-    def __init__(self, builder, document):
+    def __init__(self, document, builder):
         if not hasattr(builder, "config"):
             raise TypeError("Builder has no config: {}".format(type(builder)))
         TextTranslator.__init__(self, document, builder)
@@ -1254,7 +1254,7 @@ def __init__(self, builder):
         self.builder = builder
 
     def translate(self):
-        visitor = self.builder.create_translator(self.builder, self.document)
+        visitor = self.builder.create_translator(self.document, self.builder)
         self.document.walkabout(visitor)
         self.output = visitor.body